The relation between malnutrition early in life and subsequent mental retardation in man has been suggested by many workers. However, the coincidence of social and psychological deprivation with early nutritional deprivation precludes assignment of a cause and effect interaction of this relationship. Thus, the need for animal studies carefully designed to demonstrate the mechanism of such an effect is evident. This Program Project is a coordinated multidisciplinary study of the role of early maternal protein undernutrition on the ontogeny of the structure and function of the CNS of the albino rat. It is hoped that the results obtained in this project will shed light on the possible role of early malnutrition on the etiology of some forms of mental retardation in man. When abnormalities of the nervous system are found, a coordinated study of the mechanisms resulting in such abnormalities takes place. If the underlying mechanism can be determined, then the abnormalities may yield to treatment (e.g., drug therapy, behavior modification).